com.linuxbox.enkive.message.AbstractBaseContentData.java Source code

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Here is the source code for com.linuxbox.enkive.message.AbstractBaseContentData.java

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/*******************************************************************************
 * Copyright 2013 The Linux Box Corporation.
 *
 * This file is part of Enkive CE (Community Edition).
 *
 * Enkive CE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * Enkive CE is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public
 * License along with Enkive CE. If not, see
 * <http://www.gnu.org/licenses/>.
 *******************************************************************************/
package com.linuxbox.enkive.message;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.apache.commons.codec.binary.Hex;
import org.apache.commons.io.IOUtils;

import com.linuxbox.enkive.exception.CannotTransferMessageContentException;
import com.linuxbox.enkive.exception.EnkiveRuntimeException;

/*
 * TODO
 *  
 * This class no longer needs to do any hash calculation. The back-end is now responsible for figuring out
 * the unique name for the document. Also, this class reads everything into a byte array, likely only to
 * calculate the hash. If possible, if this can keep track of an InputStream for the document and possibly
 * the MIME type, file extension, and encoding type (base64, quoted printable, 7bit, 8bit, binary) that
 * would be sufficient.   
 */

public abstract class AbstractBaseContentData implements BaseContentData {
    private static final String HASH_ALGORITHM = "SHA-1";

    protected byte[] data;
    protected byte[] hashBytes;
    protected String hashString;

    public AbstractBaseContentData() {
        super();
        data = null;
        clearHash();
    }

    @Override
    public InputStream getBinaryContent() throws ContentException {
        return new ByteArrayInputStream(data);
    }

    public byte[] getSha1() {
        // only calculate hash when requested
        if (hashBytes == null) {
            calculateHash();
        }
        return hashBytes;
    }

    @Override
    public String getSha1String() {
        // only calculate hash when requested
        if (hashString == null) {
            calculateHash();
        }
        return hashString;
    }

    @Override
    public void setBinaryContent(InputStream contentStream) throws CannotTransferMessageContentException {
        clearHash();
        try {
            ByteArrayOutputStream output = new ByteArrayOutputStream();
            IOUtils.copy(contentStream, output);
            IOUtils.closeQuietly(contentStream);
            IOUtils.closeQuietly(output);
            data = output.toByteArray();
        } catch (IOException e) {
            throw new CannotTransferMessageContentException(e);
        }
    }

    @Override
    public void setBinaryContent(String content, Charset encoding) {
        clearHash();
        data = content.getBytes(encoding);
    }

    @Override
    public void setByteContent(byte[] content) {
        clearHash();
        data = content;
    }

    protected void clearHash() {
        hashBytes = null;
        hashString = null;
    }

    protected void calculateHash() {
        // if there's no data then there's no hash
        if (data == null) {
            clearHash();
            return;
        }

        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance(HASH_ALGORITHM);
        } catch (NoSuchAlgorithmException e) {
            throw new EnkiveRuntimeException(e.getMessage());
        }

        md.update(data);

        hashBytes = md.digest();
        hashString = new String((new Hex()).encode(hashBytes));
    }
}